Congestive heart failure (CHF) is one of the leading causes of cardiovascular morbidity and mortality. With the aging population CHF treatment has become a major public health issue. Recent advances in management of CHF include implantation of biventricular (Bi-V) pacemakers to achieve cardiac resynchronization (CRT). Numerous studies have shown than significant improvements in patients' functional capacity and longevity can be attained when appropriately selected patients receive CRT. Many of the early published trials supporting the benefits of CRT primarily focused on using the patients' intrinsic atrial rate to drive the ventricular pacing rate (VDD mode). However, in clinical practice many CRT recipients are programmed in the dual chamber pacing mode (DDD), which may increase the likelihood of atrial pacing especially given the possibility of better beta-blocker titration with atrial rate support.
By necessity successful delivery of CRT requires biventricular pacing-induced activation of both ventricles prior to intrinsic conduction through the atrioventricular (A-V) node. The programmed A-V delay, or the time between atrial sense/pace and ventricular pace, thus must be sufficiently truncated to preempt intrinsic AV conduction. Programming the A-V delay to optimize left ventricular (LV) filling continues to remain challenging. Many centers perform so-called “A-V optimization” studies using 2-D Doppler echocardiography after implantation. These optimization studies are frequently time consuming and increase the resources required for each implantation. Thus, if the optimal A-V delay could be calculated during initial implantation, such studies would become less necessary.
Applicable prior art relating to CRT includes U.S. Pat. No. 6,885,889 entitled, “Method and Apparatus for Optimizing Cardiac Resynchronization Therapy Based on Left Ventricular Acceleration,” and U.S. Pat. No. 6,871,088 entitled, “Method and Apparatus for Optimizing Cardiac Resynchronization Therapy,” the entire contents of which are hereby incorporated by reference herein.